Adjuster equipment for evaporators



Dec. 29, 1931.

s. F, GR OVE ADJUSTER EQUIPMENT FOR EVAPORATORS 2 Sheets-Sheet Filed Mayl, 1929 Dec. 29, 1931. s. F. GROVE 1,838,671

ADJUSTER EQUIPMENT FOR EVAPORATORS Filed May 1, 1929 2 Sheets-Sheet 2Patented Dec. 29, 1931 SAMUEL FELTONTQGROVE, F SWARTI-IMORE, PENSYLVANIA- ADJusrER EQUIPMENT For; nveronerons Application filed m 1,1929. Serial No.3;9,4s5.-

My invention'relates to multiple evapora tors or the like withparticular reference to equipment thereof for eifectlng automatic adustments of inlet and outlet valves,e1the'r 5 or both. r V V A purposeof my invention is to ma nta n uniformity n the product from an evaporaetor and'uniformity in the operating condi tions inside an evaporator;either or both. 7'

A further purpose. is to make the density of the concentrated'liquorflowing away from an evaporatorautomatically adjust an outlet valvecontrolling the outlet flow of the liquor product in a way to secure aliquor product of substantially uniform density; 1

A further purpose is to combine a density control of an outlet valv'efrom'an evaporator with a constant level control of aninlet valve to theevaporator preferably operating the evaporator continuously, making anyin-'. crease 1n density effect an increased opening in the outlet valveand the resultant fall in level inside the evaporator effect anincreased opening in the inlet valve to the evaporator and vice versawhen the density of the liquor output decreases. v j a i A furtherpurpose is to suspend a liquid container and an operating weight uponopposite sides of a pivoted balance at horizontal 3G distances from thepivot that are relatively variant with variation in the angulardeflection of the balance, making the ratio of the horizontal length ofthe arm of thelsuspended container to thatofthe suspended weight decrease with increased downward deflection of the container and viceversa, and to usethe balance to adjust an inlet or an outlet valve to anevaporator or otherrreservoir byfusing a characteristic of the liquidgoing to or com avoid crystallization of the liquid inside thecontainer. v to a j j p Further purposes will appear n thespecifications'and 1n the claims.

structure embodying my invention and shows ing from orwithin thereservoirito vary the 7 weight of the liquldin thesuspended conl haveelected to illustrate-my invention in one main form only, with minormodificationsand show it applied to a multiple'evaporator, showing theevaporatorjdiagrammatically and my balance valve adjuster equipmentapplied to maintain constant liquid levels inside the'differentevaporator units, and to maintain uniform density'in the dis chargeliquor from the last unit evaporator.

Figure 1 is a diagrammatic el'evationof my balance valve adjustersapplied to a mul-J tiple evaporator, the showing of theevaporatorsbeingintended as a conventional showing for anystructureto which my equipmentis adapted to be applied. a r j 'j T Figure Qis an enlarged fragment ofFig ure 1.

Figure 3 is a broken elevation correspond ing to part of Figure l butshowing a detail modification. j

Figure 5 is afragment ofFigure 1 but showing difl'erent connections foradjusting the outlet valve to maintain an output of constant density. VFigure 6 is a fragmentary elevation partlysectioned and to an enlargedscale showing a' desirable form of my valve adjuster applied to adjustan inlet valve of an evapo rator, the balance mechanism shownconnectedto adjust an inlet valve to maintain constant liquid level inside theevaporator being equally adapted to adjust anoutlet valveto maintain aliquor output at .a constant density. a Figure 7 is a diagrammatic curveused to illustratethat a balance embodying one .form of my valveadjuster is desirably operated at either one of two different ranges ofdeflection. V

'Like numerals refer to like-parts in all figures' Describing inillustration'and not in limitation and referring to the drawings Figure1 shows a multiple evaporator equipment that embodies my inventionindicated more or lessdiagrammatically in the operation of'concentratinga dilute chemical liquor, for example, a solution of sodiumferrocyanide,preparatory to obtaining the crystallized salt when theconcentrated liquor discharging from the last evaporator unit cools.

The weak liquor is fed by gravity from a suitable container 10 through apipe 11 having a control valve 12 into the first evaporator 13.

The first evaporator is heated by hot pipes 14 that are preferablyheated by steam v a porized from the partially concentrated liquor 16 inthe third evaporator 17. This steam leaves the third evaporator'througha- .1 liquor in the second evaporator being led away through a suitablevapor outlet pipe 26 to a vacuum pump and condenser not shown.

The additionally concentrated liquorpasses out of the second evaporatordown through a pipe 27 centrifugalpunip 28, ipe having a control valve30 into the t iird evaporator 17 which is heated by low pressure steampipes 31.

In usual operation there may be a vacuum of about eighteen inches ofmercury in the-first evaporator, a vacuum of about twenty-six inches ofmercury in the second and a vacuum of about ten inches of mercury in thelast evaporator.

It will be seen that with this condition the liquor tends to flow fromthe first evaporator-to the second, but that pump 28 is required todeliver the liquor from the second evaporator to the third.

fThe concentrated liquor from the third evaporator is shown led outthrough pipe 32, control valve 33, centrifugal pump 34 and dischargepipe 35 to an overflow at 36 into a raised distribution tank 87 whenceit flows by gravity through valves 38 to difierent cool ing tanks notshown, the dissolved salt crystalliz'ing out of the concentrated liquoras the liquor cools.

The operation is desirably continuous and uniform, and I connect a valveadjuster unit 40 to maintain the level of liquor inside the firstevaporator constant by suitable adj ustments of the valve 12.

I connect a second valve adjuster 41 to the control valve 24 so as tomaintain the liquor level in the second evaporator 22 constant.

Iconnect a third valve adjuster '42 so as to maintain the liquor levelin the third evaporator constant by adjustment of the valve 5 30, and Iconnect a fourth valve adjuster 43 to control the outlet valve 33 fromthe last evaporator to secure a discharge liquor of substantiallyconstant density.

The operation of the individual adjuster units is best illustrated inFigure 6.

A balance 44, shown as a wheel, has pivot support at 45 and suspends onopposite sides and at relatively variant horizontal distances from thepivot, a weight 46 and a hollow container 47.

The container and weight are respectively supported upon opposite sidesof the wheel by chains or flexible metal ribbons 4S and 49.

The flexible connection 48 suspending the container 47 is fastened tothe wheel circumference at a point 50 lower than the horizontal throughthe pivot 45, while the connection 49 suspending the weight is fastenedto the wheel circumference at a point 51 higher than this horizontal.

Turnbuckles 52 and 53 are inserted in the suspending members 48 and 49.

The container 47 has upper and lower flexible tube connections 54 and 55into the evaporator 56, respectively above and below the surface of theliquor 57 that is to be maintainedat a constant level by adjustments ofa valve 58 in an inlet pipe 59, the evaporator having a continuousoutlet not shown.

The weight 46 and suspending member 49 have operating connection at 60with the out or end of the valve handle 61 which is shown provided withan angularly adjustable connection with the movable element 62 of thevalve.

The weight 46 on one side of the balance exerts a turning moment that issubstantially constant and that is adapted to be balanced by theoppositely directed turning moment exerted by the combined container andliquid on the other side of the balance at angularpositions of thebalance that are variant according to the height of the liquor in theevaporator.

Any rise of the liquor inside the evaporator 56 results in acorresponding rise of the liquor inside the container 47, and theresultant increase .in weight tends to move the container 47 downward,turning the balance upon its pivot to partially close the valve againstthe retractive force of the weight 46.

lVhen'the container moves downward the effective length of its arm withrespect to the balance pivot shortens in that its point of suspension 50moves inward, tending to lessen the turning moment exerted by thecontainer, while the additional liquid which enters the container byreason of its downward movement increases the weight upon the arm,tending to increase the turning moment exerted by the container.

The moment exerted by the container 4? thus either increases ordiminishes when the container moves downward according to whether theincrease in the suspended weight by reason of the additionalliquorentering the container-is proportionatelygreater or less than thediminution of the horizontal arm of the suspended container by reason ofthe point of suspension 50 moving inward. Y

If the point of suspension .50 is near a po sition horizontally outwardfrom the balance pivot, anychange in the angular posiion of thebalanceeffects a change. in the length of the arm that is proportionately smallcompared to the oppositely effective change in weight unless thecontainer be of very small sectional area,while the reverse is trueiithe point 50 is near a position vertically downward from the balancepivot.

I may operate the balance in either'one of two different ways which willbe best understood from a consideration of the curves shown in Figure 7.

The abscissa: on this curve represent different angular positions of thebalance as determined by the angular position of the point of suspension50 of the container measured from a point horizontally outward from thebalance pivot, the point d on the curve corresponding to the position ofthe balance at which the. point 50 is horizontally outward from thebalance pivot.

Curve A indicates the 'torque'or turning moment exerted by the containerand its liquid at these difierent angular positions, as-

' suming the balance moved by hand to these positions and assuming aconstant level of liquor inside'the evaporator. 1' i The horizontal lineB indicates the opposing and substantially uniform torque exerted by thecounterweight 46. I

VJherever the curve A is above thecurve B, the balance it free to'movewill deflect in di rection to lower the container 47 wherever the curveA is below the curve B, the balance it free to move will deflect indirection to raise the container 47, and atpositions correspending topoints of intersection'between the curves A. and B, the balance willhave no tendency to move in either direction.

In accord with the curve A, the container 47 is wholly above the surfaceof the hquor in the evaporator between the points (Z and e,

the liquor first entering the container with a resultant sharp increasein torque when the container is moved downward beyond thejposition e.

' As the torque A is equal to the product of the total weight suspendedat the point 50 times the horizontal distance of this pointoutwardlyfrom the balance pivot the torque increases when the container is moveddown- .ward beyond the point 6 until at about the point f the rates orweight increase and arm decrease are equal. r v V Beyond the point f thearm decreases faster than the weight increases, resulting in aprogressivelyjdecreasing torque for all positions progressively beyond.the point f.

I The horizontal line C indicates the assumed level of theliquor in theevaporator, and the curveG shown dotted indicates the requisitechange-from this level to make the torque eX- 'ing to circumstance.

If the container is lowered by suitable adjustment of the turnbuckle 52so that with the givenlevel of liquor in the evaporator the liquorbegins to enter the container at the point g, the curveof torque exertedby the container and its'liquor for positions down wardly beyond thepoint 9 will be about as indicated by the curve A". r

lfthe container in its lowered'position is deflected downwardly from thepointy, or if while the container-is at the point thelevel of liquor intheevaporator rises, the balance will-tend to keep on deflecting and iffree to movewill ultimately come to rest at the point h.

In Figure'6 I have limited the downward With normal continuousoperation, there is acontinuous flow into the evaporator andanother-continuous" flow out of it. 7

. I may give the valve 58 setting such that when the container 47 isdown upon its stop 64 the inflow through the valve is slightly less thanthat needed to maintain the level inside the evaporator constant, andwhen the container is in its high position corresponding to the pointyou Figure 7 the valve is open far enoughto make the flow through thevalve slightly in excess of that needed to maintain theliquor intheevaporator at'cons'tant level.

In operation the container'then has a small range ofvertical movement.

As soon as the liquor level falls far enough for'tlie liquor to leavethe container, the container rises and slightly increases the opening ofthe valve which in. due course results in a- .suflicient raising of thelevel oi'the liquor inthe evaporator toagain flood the bottomofthecontainer, causing the container to sink and again sufficientlylessen the inflow of liquorthroughthe valve; to start the level inside athe evaporator to gradually sink, the

sequence of operations repeating itself over 1 and overqwith ,a verynarrow corresponding fluctuation of-thelevel of the liquorin the"stantially no fluctuation in the level inside the evaporator.

Any increase in the height of the liquor increases the angulardeflection of the balance and slightly closes down the valve, and viceversa, any decrease in the height of the liquor decreases the weightinside the container and slightly opens the valve.

As a result the valve gravitates to the position for maintaining theliquor in the evaporator at constant level, and there may be no visiblechange in either the setting of the valve or in the level of the liquorin the evaporator over long periods.

hen used to control the level of a hot liq nor that will depositcrystals on cooling I provide the container with a small inlet flow ofdiluting liquid so as to maintain the liquor in the suspended containersufficiently dilute to avoid the formation of crystals in the container.

In the illustration I connect the bottom of a suitably supported glassfunnel 66 to the top of the suspended container 47 by a suitableflexible tube 67 and flow a small stream of diluting liquid into thefunnel and thence to the container 47, thus providing a small sight-fecddelivery of diluting liquid into the liquor within the container.

I have found in practice that the wheel form of balance shown in Figure(Sgives excellent satisfaction. Obviously however, I may widely vary thedetail construction of the balance and in Figures 1, 3, and 5 show thevalve adjusters each including a balance in which the weight l6 andcontainer 47 are respectively suspended upon arms 68 and 69 that divergedownwardly from opposite sides of the pivot In this arrangement downwarddeflection of the container simultaneously decreases the length of thearm of the container and increases the length of the arm of the weight,

and any range of unstable equilibrium such as that indicated by anintermediate portion of the curves of Figure 7, will be non-existentunless the container is of abnormally large sectional area.

The two forms of balance illustrated are to be understood as merelyexamples of many forms in which the ratio of the horizontal arm of theweight to that of the container will increase whenthe container movesdownward and vice versa when the container moves upward.

An important feature of my invention is the adaptation of the balance tocontrol the outlet valve of the last evaporator in a way to maintain thedensity of the discharging liquor from the last evaporator substantiallyconstant.

I use the density of the discharging liquor to control a water-levelthat in turn controls the outlet valve from the evaporator.

I provide means for balancing a column of water of variable depthagainst a column of the discharging liquor of definite and preferablyconstant depth, transmitting the pressure from the foot of the column ofthe liquor to the foot of the balanced column of water in any suitableway; either by a suitable diaphragm (Figures 1, 2 and 5) or by an airtrap (Figure 3).

In Figures 1 and 3 the column of liquor used to support a balancingcolumn of water that in turn controls the operation of the valveadjuster is obtained by discharging all of the liquor through a verticaloverflow pipe 35 into an elevated distributing tank 37.

In Figure 1 the adjuster 39 is operated by variation in the density ofthe column of liquor in. the pipe '35.

A column of water or of other suitable liquid (herein called water) hasits lower end at 70 inside a collapsible diaphragm member 1 that issurrounded by the liquor, and has its upper end in the container 4,suitable flexible connection being provided at 72 be tween the bottom ofthe container and the top of a pipe 73 ending at its lower end in thediaphragm member.

The container 47 is open to atmosphere at 74 and contains a variantquantity of water according to the variant pressure tran smittcd againstthe collapsible diaphragm member 71 by the liquor in the pipe 35.

Any increase in density of the discharging liquorincreases the pressureat the foot of the column and partially colla-pszes'the d iaphra gmmember, thereby increasing the quantity of water in the container 47 anddeflecting the balance to adjust the valve 33 in direction to reduce thedensity of the discharging liquor.

This adjustment is one to somewhat open the valve which initially lowersthe level of the liquor 16 in the evaporator and thereby results in anopening adjustment of the valve 30 to maintain the level 16.

The operation is exactly the reverse if the density of the dischargingliquor lessens. The reduced pressure upon the diaphragm member 71 thenpermits the diaphragm member to expand which reduces the amount ofliquid in the container r7 resulting in a movement of the balance topartially close the valve 33 which in turn eiii'ects an adjustment ofthe valve 30 toward closure, due to the level of the liquor in theevaporator beginning to rise.

The diaphragm 71 is shown diagrammatically and in practice may have veryconsiderably greater internal. volume as compared to that of thecontainer 4-7 than would appear to be indicated by Figures 1 and 2.

It will be apparent that almost any desired delicacy of adjustment maybe obtained by suitable increase in the lengths of the columns of liquorand water respectively.

Figure 3 shows a detail modification of the structure in Figure 1 foradjusting the discharging liquor to constant density.

As 1n Flgure l the liquor from the evaporator 16 discharges through anoverflow pipe 35 into the elevated distributing tank 37 whence it flowsby gravity to the cooling tanks not shown. 7;

Instead of the diaphragm member 71 for transmitting the pressure of thecolumn of liquor to the foot of a balancing column of water that has itsupper end in the container 47 1 provide any suitable air trap betweenthe two columns.

The air trap, preferably glass, is shown comprising inverted bottlemembers 75 and 76, there being a tubular connection 77 be tween thetrapped air in the upturned bottom of one bottle and the. air in theupturned bottom of the other bottle.

The bottle 75 forms a portion of the overflow conduit to thedistribution tank, being in effect a coupling member between verticallyspaced portions of the pipe 35 which extends downwardly through thebottom for some dista ce at Z8 into the bottle. The pipe has a suitableseal with the bottom of the bottie and the liquor rising up around theend air.

he operation is as already described except that the variations ofpressure incident to small changes of liquor density are transmitted tothe foot of the water column through the air trap insteadof through thediaphragm. It will be seen that an increase in density will in bothforms increase the back pressure uponthe pump and the pressure tismitted to the foot of the water column that rises into and variantlydeflects the container 4, increasing the amount of water in thiscontainer and eflecting an increased deflection of the balance 68.

In the structure of Figure 5, I permit a b passing stream of liquor tofiow into the vertical pipe which overflows at 86 into the top of theevaporator.

The inlet 87 into the Vertical pipe is very small as compared to thepipe area so that there is a constant head of liquor. upon a diaphraginmember 1 whlch may be in every Way similar to the diaphragm member'i'lof igure 2 and is used to adjust the valve 33 exactly as in thestructure shown in Figure 1.

In view of my invention and disclosure variations and modifications tomeet individual whim or particular need will doubtless become evident toothers skilled in the art and I claim all such in so far as they arereasonably covered by the spirit and scope of the invention and claims..7

Having thus described my invention what I claim as new and desiretosecureby Letters Patent is 1. In a regulator for controlling theheight of a hot liquid solution in a recepoi the pipe forms a liquorseal for the trapped tacle having an inlet valve and an outlet, aclosedliquid container, flexible connections from near the top andbottom thereof adapted to connect into the interior of the receptacleabove and below the surface of the liquid in the receptacle, connectionsadapting the container to control the inlet valve, in combination withmeans continuously delivering a small stream of non-precipitating liquidinto the container to prevent precipitation within the container.

2. In evaporator equipment, a valve, means adapting adjustment of thevalve to adjust the density of the evaporator output, a valve adjusteroperatively connected to the valve, a column of liquid having an upperend inside and operatively controlling the movement of the adjuster, andmeans operative by variations in the density of the liquor in the.evaporator for controlling the elevation of the said upper end.

8. An evaporator for concentrating dilute liquor, an inlet valve adaptedto continuous- 1y feed dilute liquor to the evaporator and an outletvalve adapted to continuously discharge concentrated liquor vfrom theevaporator in combination with connections for varying the elevation ofa column of liquid according tothe density of the discharging SAMUEL F.GROVE.

